Automated charging plug within a parking curb.
Overhead view of car park showing possible charging connection lines selected by the multiplexer.
Even with the CurrentPlex system integrated, the car park still appears uncluttered.
Mobile application to activate charging remotely and update the car's charge state.
What it does
CurrentPlex is a car charging system that solves 3 main problems with car chargers. Firstly, the limited availability of car chargers. Secondly, car charging will add additional load to the power grid. Thirdly, the inconvenience of charging a car.
As avid supporters of electric cars, we look forward to the mass adoption of electric vehicles. However, we realised that despite governments of many countries providing benefits to electric vehicle owners, there are still more gasoline cars sold compared to electric cars. Upon researching, we identified that the inconvenience of charging a car to be a key factor causing this result. Our team took inspiration for the queue system from queues in the telecom support services while the inspiration for the automated plug was drawn from a 3d-printer.
How it works
CurrentPlex comprises two components. First, the power supply is connected to multiple cars charging plugs via a multiplexer. This allows the power to be directed to any plug at a given time enabling multiple cars to be charged one after the other without moving the car. The second component is an automated charging connector housed within a parking curb. When a car is parked, an infrared dot projector and sensor which are nested in the curb identifies the position of the charging port on the car. The charging plug is mounted on a pair of rails with belt pulleys allowing the plug to be adjusted laterally and horizontally. The rails are fitted to a container with a rack and pinion mechanism to raise the plug vertically. The connector is attached to the plug housing via springs to enable it to move within a limited range. This connector will then be accurately and securely attracted to the car charging port via an electromagnet mounted within the car’s port.
The CurrentPlex was developed with 3 subsystems. First, for the power supply and multiplexer setup, we designed a simple addition to a charging circuit by adding a multiplexer and programmed a microcontroller to monitor the entire operation and control the multiplexer. Next, we developed an application by considering features that would benefit the user. Following this, our team designed the interface on photoshop to test the user interface and finally moving on to the complete app which links to the charger's microcontroller which doubles as a server. Thirdly, we developed the automated charging connector. For this, we started with testing concepts with basic CAD simulations to identify potential drawbacks. The first design was a double-hinged latch which was inconsistent and could cause damage to the car. The second attempt was to use an 8-degrees of freedom robot arm but it was overly complex and requires a large space. We finalised on a rail system similar to that used in a low-cost 3d-printer and managed to fit it within the curb to be unobtrusive.
How it is different
The CurrentPlex system is simple as it utilises proven technologies such as wired connectors which is more power-efficient compared to wireless charging and utilises an alignment setup compared to using a robotic arm. Additionally, it is more effective in terms of cost and use of space due to the efficient package of the charging plug and the need for less power supply for car-park charging. The charging plug can also be easily installed in parking lots as it is housed within a curb which is above ground.
We hope to create a scale model of the plug to test the accuracy in real-world operation with complete integration of the microcontroller and the mobile application. Ultimately we hope that this system can be implemented to solve the charging crisis faced by electric car owners to advance the adoption of electric vehicles.